The son of King
Brochfael Ysgythrog and Arddyn Benasgel, the daughter of King
Pabo Post Prydain of the Pennines, and St.
Tysilio's elder brother. This late 6th century King of Powys apparently had very white legs,
hence his name of White-Shanks. Though, the epithet may be a
mistaken rendering of "Carrwyn," of the White-Chariot.
His horse, 'Du Hir Tynnedig' (Tall Black-Tinted One), is named as
one of the three chief steeds of Britain.

Cynan
was a powerful king remembered in the poems of Taliesin. But, despite his
probable identification with 'Cynan of the Prophecies' who was expected to
free the British from Saxon oppression, his armies mostly fought against
his fellow Celts. He had victories from Ynys Mon (Anglesey) to Gwent and
Dyfed, and even threatened Dumnonia. His forces were, apparently, most
successful in Brycheiniog, which Cynan seems to have conquered for a time.
The Powysian monarch encamped on the River Nedd, but the monks of
Llancarfan negotiated a peace which stopped him from continuing further
into Glywysing. Cynan was a Christian himself, a patron of St.
Beuno to whom he had given land near Corwen.

Cynan married Gwynwenwen daughter of Prince Domangart mac Aidan
of the Scots; and they had at least three children: Selyf Sarffgadau,
Dinogad and Afandreg Ddu, the wife of King Cadfan
the Wise of Gwynedd. Upon his death, Selyf succeeded to the
throne of Powys.